1. Technical Field
The present disclosure relates to a light emitting device mounting structural body in which a light emitting device is mounted on a wiring substrate.
2. Background Art
In recent years, light emitting diodes (LEDs) have been used in various fields, as light sources for lighting devices or display devises. Particularly, many side-emission type (side-view type) LEDs are used in the field of backlight for liquid crystal display devices such as TVs, mobile phones, monitors, and indicators, with increasing demands for smaller size and light weight along with the expanding multi-functionality. A side-emission LED is mounted with its light emitting surface perpendicular to an upper surface of a wiring substrate so that light is incident on an end surface of a light guide, allowing uniform emission luminance substantially over the whole area of a screen of a display or the like.
Such a side-emission LED may be provided with a pair of step portions on the bottom-surface of the housing for emitting light in the front direction of the housing, as illustrated in JP 2006-19313A. An outer lead portion of each of the lead terminals which are integrally formed with the housing is arranged with bent shape along the housing, at each of the step portions. The bottom surface of the housing and the bottom surface of the electrode portions are positioned approximately flush with each other, which allows for stable mounting of an LED indicator on a circuit board. Further, a variation in height of the LED indicators after mounting can be reduced.
JP2003-218400A discloses a light emitting device which has a chip type light emitting device provided with a connection terminal at both of the longitudinal sides, and a wiring substrate for mounting the chip type light emitting device. The wiring substrate is provided with a portion of a cut part for embedding the chip type light emitting device. Thus, a decrease of a thickness in a height direction of the chip type light emitting device can be obtained, which allows securely fixing the light emitting device on the wiring substrate.
Further, JP2003-135280A discloses a backlight having a light emitting diode, in which a lower portion of a package body of the light emitting diode is projected in the same direction as the terminal, and the lower portion is housed in a recess of the substrate. With such a configuration, the mounting height of the light emitting diodes in the backlight can be reduced.
With the configuration as described above, a light emitting device having good mountability to a substrate member can be formed. Also, a thin-type backlight can be formed. Further improvement in the emission output has been addressed and in order to accomplish that objective, further increase in the light emitting region seems to be effective. However, in the backlight described in JP 2006-135280 A, a light guide plate is arranged on the substrate, so that the emitted light from a window of an LED which is housed in the recess cannot be incident in the light guide plate.
The present disclosure is directed in view of the disadvantages outlined above, and is aimed to provide a light emitting device mounting structural body which allows an increase of light emitting region while facilitating mounting of a light emitting device on a wiring substrate, and which also allows efficient incident of light emitted from the expanded light emitting region onto the light guide member.